Will WRT54G Do What I Want?

I would like some solid pointer advice to set me off in the right direction, please.

I need to extend the range & scope of my wireless network.

I have a BT ADSL router with a Netgear 302 Access point plugged into it.

I then have a 50m clear line-of-sight to my flat where I want to install "SOMETHING" that has 4 ethernet ports, two aerials (the netgear has Send & Receive antenna so would like the receiver to have the same) that I can plug my two PCs into and they will then be able to access the internet.

I have seen the terms "bridge" and "wireless switch" bandied about, and I took me a fancy to the WRT54G (two aerials, plenty of config options).

Do you agree? If so, what firmware do you think I should use and what do I want the router set up as?

I am normally the go-to guy for technical questions, but I am a bit out of my depth with wireless networking once it gets complicated.

I have a similar setup working at my folks' place where I share an internet connection between a workshop and their house which has several computers. I do this using a Linksys router to manage the connection and an Engenius outdoor AP(the one with an external antenna connection) mounted outdoor under an awning at the shop building a high gain dish style antenna from Hyperlink. This sends the signal to their house which is about 150ft away and then it goes through several walls before reaching the office. I'd say a total of about 180ft with obstructions.

Inside I have a WRT54GS V5(about a 20 dollar E-Bay purchase) running DD-WRT micro V24 SP1. It's connected to two desktop systems using wires yet it will also allow my Dad to connect via wireless using his laptop anywhere in their good size house. On the WRT54G I have a Linksys or similar high gain(longer) 7Dbi I believe antenna.

This setup has been working VERY reliably and in DD-WRT the signal strength is generally about 50%. I used the directions on this page:

To get DD-WRT set up correctly. Right now the computers in the house are on a different subnet than the ones in the workshop but it all works just fine and internet surfing speeds etc don't seem to be effected at all. I'm using WPA security on the network. When my nephews are visiting and they have their Nintendo DS's I also enable a virtual WLAN with a different SSID for them because the Nintendo doesn't do WPA. It all works using one little box which is very cool.